Low power and Lossy Networks (LLNs), e.g., sensor networks, have a myriad of applications, such as Smart Grid and Smart Cities. Various challenges are presented with LLNs, such as lossy links, low bandwidth, battery operation, low memory and/or processing capability, etc. Many LLN link technologies use Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) for media access, which has the benefits of being very flexible to varying traffic demands within the networks.
A significant challenge with CSMA/CA is its relatively high per-packet overhead. In particular, to perform collision avoidance, a transmitter must wait a minimum inter-frame spacing delay along with an additional random backoff delay to contend for the channel. To help reduce the per-packet overhead, LLN technologies have been turning towards larger frame sizes (maximum transmission units or “MTUs”) to amortize the cost of acquiring a channel over larger amounts of data, thus increasing the overall throughput of the system. However, while larger packet sizes can improve the overall throughput of the system, they can also significantly hinder the communication latency, since only one device may transmit to a given receiver at a time a shared communication medium.